/* global self */
import { Decrypter } from 'aes-decrypter';
import { createTransferableMessage } from './bin-utils';

/**
 * Our web worker interface so that things can talk to aes-decrypter
 * that will be running in a web worker. the scope is passed to this by
 * webworkify.
 *
 * @param {Object} self
 *        the scope for the web worker
 */
const DecrypterWorker = function(self) {
  self.onmessage = function(event) {
    const data = event.data;
    const encrypted = new Uint8Array(
      data.encrypted.bytes,
      data.encrypted.byteOffset,
      data.encrypted.byteLength
    );
    const key = new Uint32Array(
      data.key.bytes,
      data.key.byteOffset,
      data.key.byteLength / 4
    );
    const iv = new Uint32Array(
      data.iv.bytes,
      data.iv.byteOffset,
      data.iv.byteLength / 4
    );

    /* eslint-disable no-new, handle-callback-err */
    new Decrypter(
      encrypted,
      key,
      iv,
      function(err, bytes) {
        self.postMessage(createTransferableMessage({
          source: data.source,
          decrypted: bytes
        }), [bytes.buffer]);
      }
    );
    /* eslint-enable */
  };
};

export default new DecrypterWorker(self);
